Colorectal cancer is cancer that occurs in the colon (large intestine) or rectum. It is often called colon cancer. Colon cancer screening is done before a person develops symptoms.
Regular screening can detect colon cancer early, making it easier to treat. Screening also enables your healthcare provider to find and eliminate any growths before they become cancerous.
Colon cancer is the third most common cancer. In the United States, there are more than 100,000 new cases each year. However, colon cancer deaths have declined steadily in recent years as more people are screened, and they get screened early.
colon cancer is called polyp That shape on the lining of the colon. Not all polyps become cancerous, and it can take years for polyps to become cancerous.
According to the American Cancer Society (ACS), the five-year survival rate for colon cancer detected early is about 90 percent. Unfortunately, only 40 percent of colon cancers are caught so early, and one-third of people diagnosed with the disease in the U.S. have not been screened before.
This article will discuss what happens during colonoscopy and other screening methods, choosing the right test, and current screening guidelines.
What happens during a colonoscopy?
A colonoscopy is a procedure to examine the inside of the colon using a long, flexible tube with a camera called a colonoscope. It is used to screen for colon cancer and other colon problems.
A successful colonoscopy requires a clean colon. You will need to restrict your diet at least 24 hours before your appointment. This means a completely clear liquid diet, including coffee, water, broth and sports drinks.
You also need to empty your bowels. Your doctor may recommend laxatives or enemas. You need to do this the night before your colonoscopy. Be sure to strictly follow all directions from your doctor.
Bowel Prep Made Easy: Step-by-Step Instructions
Arrange for someone to take you home after the colonoscopy. You will be sedated (medicated to make you drowsy and relaxed) during the procedure, and it is not even safe to drive for at least 8 hours after the colonoscopy.
Colonoscopy is performed by a gastroenterologist, a doctor who specializes in diseases of the digestive tract. This process takes about 30 to 60 minutes. You’ll get a sedative drug through an IV in your arm. You’ll be connected to a monitor that will record blood pressure, blood oxygen levels, and heart rate.
During a colonoscopy, a gastroenterologist will use the colonoscope to examine the lining of your colon and check it for abnormalities.
The colonoscope is inserted through the rectum and advanced into the colon. It is curved so it can be moved to examine the colon. It also blows air into the colon to help it expand so it can be seen more clearly.
If doctors find anything unusual during a colonoscopy, they will take a small sample for analysis (biopsy). If any polyps are found, they are removed during surgery.
How Healthcare Providers Diagnose Colon Cancer
Colon cancer screening methods
A colonoscopy isn’t your only option to screen for colon cancer. Other screening methods are sigmoidoscopy, virtual colonoscopy, stool immunochemical test, stool occult blood test, or stool DNA test.
A sigmoidoscopy is a diagnostic test used to examine the sigmoid colon, the lowest part of the colon that holds and passes stool. Sigmoidoscopy can be used to take tissue samples and remove polyps or hemorrhoids (swollen veins in the rectum and anus). It also screens for colon and rectal cancer.
A sigmoidoscopy uses a thin, flexible tube called a sigmoidoscope, which has a tiny light and camera. The sigmoidoscope is inserted into the anus and moved slowly through the rectum to the lower part of the colon. The tube is also used to blow air into the colon to inflate it and improve visibility.
Just like a colonoscopy, you need to prepare for the procedure. You should stop eating solid foods at least eight hours before. You will also need to use an enema to clear your colon before surgery. You will need someone to drive you home because you will be sedated during the procedure.
A virtual colonoscopy helps your doctor see the inside of your colon and rectum. It is used to look for polyps and to check for colon and rectal cancer. A virtual colonoscopy uses a computed tomography (CT) scanner and X-rays to take a 3D image of the colon that can be seen on a computer screen.
The test does not involve sedation, but requires some preparation. To prepare, your doctor may suggest some dietary changes. Before surgery, you’ll also need to drink contrast, a fluid that makes the colon and rectum easier to see on scans.
What is a virtual colonoscopy?
Fecal immunochemical test
Fecal immunochemical tests look for antibodies to detect the presence of hemoglobin (the oxygen-carrying protein in red blood cells) in the stool, which can be an early sign of colon cancer.
The test is becoming more popular because it is non-invasive and can be collected in the privacy of your home. Unfortunately, tests are not always accurate, and a positive test may require a colonoscopy.
Fecal occult blood test
A fecal occult blood test looks for hidden (occult blood) blood in the stool. The source of blood can be anywhere in the gastrointestinal tract, and it can be associated with many different diseases, including colon cancer.
The test is less used than other colon cancer screening methods, and there are newer stool tests that can produce better results, including stool immunochemical tests.
Fecal DNA testing
Fecal DNA testing is a non-invasive tool for adults 45 and older with an average risk of colon cancer. Fecal DNA tests look for microscopic blood in the stool as well as DNA changes and mutations in the stool, which may include precancerous polyps and/or cancerous tumors.
Fecal testing is done by collecting a stool sample at home and sending it to a laboratory for testing. Fecal DNA analysis will use sensitive detection methods to look for multiple DNA markers and mutations. Fecal DNA testing has a high rate of detection of colon cancer in the early stages.
In 2014, the U.S. Food and Drug Administration (FDA) approved Cologuard, making it the first DNA stool test to screen for colon cancer. Since then, it has become the screening method of choice for colon cancer.
Choosing the Right Colon Cancer Test
Your healthcare professional is best placed to advise you on which colon cancer screening method may be best for you. They know about your personal and family cancer history and any other risk factors. They will recommend that you start screening at age 45.
If you have an average risk of colon cancer, your healthcare provider may recommend a home screening method. Fecal DNA tests, fecal occult blood tests, and fecal immunochemistry tests can all be collected in the privacy of your bathroom.
These home-collected tests are convenient, accessible, and effective. But if these tests detect anything, you will need a colonoscopy.
Full colonoscopy is the most accurate screening method. But it takes preparation, composure, and a day or two of work.
Depending on which part of the colon your doctor wants to see, a sigmoidoscopy may be considered. Sigmoidoscopy is less invasive because it only looks at the lower part of the colon, whereas colonoscopy looks at the entire colon.
If time is an issue for you, a virtual colonoscopy may be an alternative to a full colonoscopy. The procedure images the rectum and colon and can be as accurate as a colonoscopy. But if the test shows polyps or other abnormal growths, you will need a colonoscopy to remove them.
Consider the pros and cons
There is no best screening method for colon cancer. Each test has advantages and disadvantages. Your healthcare professional can educate you on the pros and cons of each test and help you decide on testing and follow-up based on your preferences, overall health, availability, and financial resources.
Study: Early diagnosis of colorectal cancer
Current Screening Guidelines
The ACS recommends that people with average colon cancer risk begin regular colon cancer screening at age 45. Screening may start earlier if you have risk factors.
People who are healthy and have a life expectancy of more than 10 years should continue screening until age 75.
After age 75 and before age 85, screening is based on personal preference, previous screening history, health status, and life expectancy. Colon cancer screening is not recommended after age 85.
The frequency of screening depends on the test method or test combination. According to the Centers for Disease Control and Prevention (CDC), stool testing should be repeated annually. Sigmoidoscopy can be done every 5 or 10 years, and a fecal immunochemical test every year.
Virtual colonoscopy is valid for five years, while if you have no increased risk factors for colon cancer, you can have a full colonoscopy every 10 years.
Screening is your best way to prevent colon cancer. Testing can find polyps and abnormal tissue early, before you develop symptoms.
Extensive screening options can detect colon abnormalities, including full colonoscopy, stool sample testing, sigmoidoscopy, and virtual colonoscopy. Your doctor can recommend a screening method based on your risk factors and preferences.
If you’ve been diagnosed with colon cancer, it can be stressful and scary. Fortunately, colon cancer is treatable, especially if it’s caught early and hasn’t spread to the colon and rectum.
Your primary care doctor can discuss typical results of your cancer. It is important to remember that information on cancer survival and outcomes is based on the general population and is often years behind, so it does not take into account the latest treatments. It cannot predict your specific prognosis or outlook.
Furthermore, the outlook for colon cancer is improving every day due to advanced and improved treatments.
Frequently Asked Questions
Is Home Colon Cancer Testing Accurate?
Home stool tests for colon cancer are reliable, study finds. You have different home test options, each with its own unique level of accuracy. Your doctor is best placed to advise you on the benefits of home testing for your unique health condition.
What are the signs that you should have a colonoscopy?
If you report frequent gastrointestinal symptoms, including constipation, irregular stools, frequent diarrhea, blood in the stool, sudden weight changes, and/or abdominal pain, your doctor may recommend a colonoscopy.
Can colonoscopy detect irritable bowel syndrome?
Colonoscopy cannot detect irritable bowel syndrome (IBS) because IBS is a functional disorder that causes symptoms but does not affect bowel tissue. The diagnosis of IBS is usually based on symptoms (spasmodic abdominal pain and changes in bowel habits) and exclusion of other disorders that cause similar symptoms.